The ‘LS48 translates four lines of BCD () input data into the 7-segment numeral code and provides seven corre- sponding outputs having pull-up resistors. Jameco Part no.: ; Manufacturer: Major Brands; Manufacturer no.: 74LS Texas Instruments [ KB ]; Data Sheet (current) [ KB ]; Representative. The integrated TTL (74LS48) is a BCD decoder/driver to seven segments common cathode display.
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Figure 3 shows how to connect the ripple-blanking terminals to give leading zero suppression on the first three digits of a four-digit display.
Figure 15 shows the basic circuit connections to be used when cascading stages. Driving a gas discharge readout with a B.
Figures 6, 7and 8 show how to modify the above circuit to drive LED common-anode displays, gas discharge displays, and low-brightness fluorescent displays, respectively. Figure 11 shows the basic way of using the B 47ls48 drive a seven-segment LCD, and Figures 12 and 13 show it used to drive other types of seven-segment displays.
Basic way of using the B to drive a seven-segment common-cathode LED display. The B can be used to drive most popular types of seven-segment displays.
The B is very easy to use, and has only three input control terminals; of these, the not-LT pin 3 pin is normally tied high, but turns on all seven segments of the display when pulled low.
These multi-part series may be just what you need! Enabling the display can be connected directly to the outputs of the IC without the use of external current-limiting resistors. Finally, the LE latch enable terminal pin 5 enables the IC to 74ls8 either direct or latched decoding operation. Way of using the B to drive a seven-segment LCD. Driving a fluorescent readout with a B. This procedure is repeated on all except the LSD, which does not require zero 74ld48. The rest of this article describes a few of the most popular 744ls48 these devices.
Figure 5 shows the basic connections for driving a common-cathode LED display.
Using Seven-Segment Displays — Part 2
A special two-part feature on how to use seven-segment alphanumeric displays. This feature enables the IC to act as a universal unit that can drive common-cathode or common-anode LED or liquid-crystal seven-segment displays with equal ease, as shown in Figures 10 to If cascaded B ICs are required to give automatic leading-zero suppression, the basic Figure 17 circuit must be modified as shown in Figure 18 to provide ripple-blanking operation.
Some of these devices have integral ripple-blanking facilities, others have built-in data latches, and a few even have built-in decade counter stages, etc. The display can be blanked at any time by driving the BL terminal to the logic-1 level. Functional diagram and pin notations of the B decade counter with seven-segment display driver.
74LS48 Datasheet(PDF) – Motorola, Inc
Need to brush 74ls8 on your electronics principles? If trailing-zero suppression is required, the direction of ripple-blanking feedback must be reversed with the RBI terminal of the LSD grounded and its RBO terminal wired to the RBI terminal of the next least-significant stage, and so on.
The CO signal is a symmetrical square- wave at one-tenth of the CLK input frequency, and is useful in cascading B counters. Method of modifying the Figure 17 circuit to give automatic leading-zero suppression. The 74LS47 has active-low outputs designed for driving a common-anode LED display via external current-limiting resistors Rxas shown in Figure 2.
When the not-LATCH terminal is pulled low, the BCD input signals that are present at the moment of transition are latched into memory and fed in decoded form to the seven-segment outputs until the not-LATCH pin returns to the high state. The segment output currents are internally limited to about 5mA at 10V or 10mA at 15V. The LT terminal drives all display outputs on when the terminal is driven to logic 0 with the RBO terminal open or at logic 1. The opening episode of this special feature explained the basic operating and usage principles of seven-segment alphanumeric displays.
They have integral ripple-blanking facilities, but do not incorporate data latches.
The IC does not incorporate a data latch and has no facility for ripple blanking. In each case, Rx determines the operating segment current of the display, and Ry determines the base current of the transistor. Driving a low-brightness fluorescent readout. Learning Electronics Need to brush up on your electronics principles? The not-BL pin 4 terminal is also normally tied high, but blanks turns off all seven segments when pulled low. Method of applying leading-zero suppression to the first three digits of a four-digit display using 74LS47 ICs.
Figure 4 shows the functional diagram and pin notations of the device, which can use any power source in the 5V to 15V range.